Changes in barley (Hordeum vulgare L. subsp. vulgare) genetic diversity and structure in Jordan over a period of 31 years

Authors: THORMANN, IMKE - Bioversity International; Reeves, Patrick; THUMM, S - Leibniz Institute Of Plant Genetics And Crop Plant Research; Reilley, Ann; ENGELS, JAN - Bioversity International; BIRADAR, C - International Center For Agricultural Research In The Dry Areas (ICARDA); LOHWASSER, ULRIKE - Leibniz Institute Of Plant Genetics And Crop Plant Research; BÖRNER, ANDREAS - Leibniz Institute Of Plant Genetics And Crop Plant Research; PILLEN, KLAUS - Martin Luther University; Richards, Christopher

Submitted to: Plant Genetic Resources: Characterization and Utilization
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/6/2017
Publication Date: 5/15/2017
Citation: Thormann, I., Reeves, P.A., Thumm, S., Reilley, A.A., Engels, J.M., Biradar, C.M., Lohwasser, U., Börner, A., Pillen, K., Richards, C.M. 2017. Changes in barley (Hordeum vulgare L. subsp. vulgare) genetic diversity and structure in Jordan over a period of 31 years. Plant Genetic Resources. doi:10.1017/S1479262117000028.
DOI: https://doi.org/10.1017/S1479262117000028

Interpretive Summary: Few studies explore changes in genetic diversity of crop wild relatives and landraces growing under on-farm management while pressured with environmental change. We assessed changes in barley landrace diversity in Jordan using seed samples collected from the same locations in 1981 and again 2012. We tested whether these changes were associated with geography or climate. Our results found that while the amount of genetic diversity in terms DNA markers and number of unique genotypes was relatively unchanged overall, local distinctiveness among landrace barley populations in Jordan was significantly reduced. Landrace phenotypes were found to be less distinct in 2012 than they were in 1981. In two sites, we observed the complete loss of local landraces during the sampling interval. Climate changed significantly over the study period, becoming hotter and drier, but we did not identify any correlation between the changes in climate and genetic or phenotypic variation. Instead, the data may reflect changes in regional seed cooperatives to distribute new heterogeneous land race accessions. This study underscores the importance of temporal variation in local landrace diversity and the effects this dynamic may have during on-farm (in-situ) conservation.

Technical Abstract: In many regions of the world, the cultivation of landraces is still common, in particular in centres of crop diversity. Significant effort has been put into ex situ conservation of landraces but limited data exist on the changes in genetic diversity that occur over time in farmers’ fields. We assessed temporal changes in barley landrace diversity in Jordan using seed samples collected in 1981 and 2012 from the same locations. We did not observe significant changes in the amount of genetic diversity, but samples collected in 2012 were more homogenous and less locally distinct. In two sites, we observed replacement of the old material. We observed a change in phenotype, and phenotypes were found to be more homogeneous among sites in 2012. Climate changed significantly over the study period, becoming hotter and dryer, but we did not identify any correlation between the changes in climate and genetic and phenotypic variations. While the amount of genetic diversity in terms of allelic richness and number of multi-locus genotypes has been maintained, local distinctiveness among landrace barley populations in Jordan was reduced.